华南绒茧蜂属二新种（膜翅目：茧蜂科）

本文报道采自广西和江西的绒茧蜂属二新种。模式标本存于湖南农学院昆虫标本室。1.黄足绒茧蜂Apanteles vitellinipes,新种(图1～4) 雌 体黑色。触角柄节、梗节、下颚须、翅基片、足(包括基节)、腹部第一背板基部凹陷部分、第1～3背板侧膜边缘和产卵管黄色;触角鞭节、前翅前缘脉、翅痣、痣后脉、产卵管鞘深褐色;其它翅脉褐色。     

Perturbation of syntrophic isobutyrate and butyrate degradation with formate and hydrogen

The effect of formate and hydrogen on isomerization and syntrophic degradation of butyrate and isobutyrate was investigated using a defined methanogenic culture, consisting of syntrophic isobutyrate-butyrate degrader strain IB, Methanobacterium formicicum strain T1N, and Methanosarcina mazeii strain T18. Formate and hydrogen were used to perturb syntrophic butyrate and isobutyrate degradation by the culture. The reversible isomerization between isobutyrate and butyrate was inhibited by the addition of either formate or hydrogen, indicating that the isomerization was coupled with syntrophic butyrate degradation for the culture studied. Energetic analysis indicates that the direction of isomerization between isobutyrate and butyrate is controlled by the ratio between the two acids, and the most thermodynamically favorable condition for the degradation of butyrate or isobutyrate in conjunction with the isomerization is at almost equal concentrations of isobutyrate and butyrate. The degradation of isobutyrate and butyrate was completely inhibited in the presence of a high hydrogen partial pressure (>2000 Pa) or a measurable level of formate (10 muM or higher). Significant formate (more than 1 mM) was detected during the perturbation with hydrogen (17 to 40 kPa). Resumption of butyrate and isobutyrate degradation was related to the removal of formate. Energetic analysis supported that formate was another electron carrier, besides hydrogen, during syntrophic isobutyrate-butyrate degradation by this culture. (c) 1996 John Wiley & Sons, Inc.     

应用HeLa细胞染色体（簇）和蛙卵提取物进行细胞核体外重建试验

将ＨｅＬａ细胞中期染色体（簇）、非液爪蟾卵提取物和ＡＴＰ再生体系混合温育,能够促使细胞核自发重建。在此非细胞体系中重建的细胞核处于一般细胞核大小范围,具有典型的双层核膜、核孔复合体、染色质、核纤层、核骨架等结构;核重建具有一个明显的过程;发现环形片层通过与核膜融合方式参与核膜和核孔复合体组装。     

Effect of polyols on the post-thawing motility of pellet-frozen ram spermatozoa

The cryoprotective effects of polyols in the absence and presence of glycerol in Tris-glucose-egg yolk based diluents on the post-thawing motility and acrosome integrity of pellet-frozen ram spermatozoa were examined. Incorporation of adonitol or xylitol (low molecular weight polyols; LMWPs) in diluents improved motility of spermatozoa in the absence of glycerol with maximum motility at 0.3 M (26.9 vs 13.3% mean motile spermatozoa; P < 0.001). Five concentrations of adonitol (0, 150, 300, 450, 600 mM) were examined in diluents containing 5 concentrations of glycerol (0, 1.5, 3.0, 4.5, 6.0% v/v). There was an additive effect of incorporation of 1.5% v/v glycerol with up to 450 mM adonitol (P < 0.001), but at higher levels of glycerol the incorporation of adonitol was detrimental to motility. The acrosome integrity of spermatozoa in diluents containing 0, 150 and 300 mM adonitol was superior to those containing 450 and 600 mM adonitol (46.1 vs 35.1% mean intact acrosomes; P < 0.05). Among the high molecular weight polyols (HMWPs) examined, better recovery of spermatozoa was obtained in diluents containing sorbitol than mannitol or inositol (P < 0.001). Sorbitol or mannitol (300 mM) improved the motility of spermatozoa in diluents without glycerol (P < 0.001), but the incorporation of HMWPs was detrimental in diluents containing glycerol. All five polyols were examined in isotonic diluents containing 360:0, 300:55, 240:110, 180:165, 120:220mM (Tris:polyol; 360 mosmol) and 6.0% v/v glycerol. There was a linear decrease in motility and acrosome integrity of spermatozoa with increasing polyol concentration in the diluent (P < 0.001) except for inositol, which was not detrimental. We conclude that the polyols examined have a cryoprotective effect on pellet-frozen ram spermatozoa except for inositol. However, in our study, no combination of polyols and glycerol was superior in terms of post-thawing motility and acrosome integrity of spermatozoa to 6.0% v/v glycerol alone in Tris-glucose-egg yolk diluents.     

Changes in Eicosanoid and Tumour Necrosis Factor-alpha Production by Rat Peritoneal Macrophages During Carrageenin-Induced Peritonitis

Changes and correlations in cytokine and eicosanoid production by blood monocytes, non-purified and purified peritoneal cells during a carrageenin-induced peritonitis were investigated for a period of ten days. The cells were isolated and stimulated in vitro. Cytokine and eicosanoid production of the non-purified fraction increased steadily during peritonitis. During the whole episode of peritonitis the production capacity of granulocytes was very low and hardly any effect on the production capacity of macrophages (Mvarphi) was observed. Cytokine and eicosanoid production of the non-purified fraction was mainly due to the presence of Mvarphi. The production capacity of the peripheral blood monocytes was not similar to that of the peritoneal Mvarphi.     

荒漠草原生态恢复与重建：人工植被推动下水分介导的系统响应、生态阈值与互馈作用

荒漠草原(生态区)横贯我国西北地区东部,生态地位十分重要。近二十年来,通过封育禁牧、退耕还林(草),植被覆盖显著改善,但是生态系统质量和稳定性依然不高。由于长期将荒漠草原单纯视作草原的一部分,对其生态系统过渡性、脆弱性和复杂性本质特征认识不足,造成了荒漠草原生态学研究与区域生态建设实践之间不同程度的脱节。在分析荒漠草原生态区未来在我国生态安全格局中突出的但是被一定程度上忽视的地位的基础上,进一步归纳了荒漠草原生态系统的一般特征,指出了生态恢复与重建研究中存在的主要问题。进而以人工植被引入荒漠草原生态工程为案例,分析了人工植被驱动荒漠草原生态恢复与重建的过程与机制,归纳了“植被-水文-土壤”互馈作用驱动生态系统层级响应模式,并展望了今后的发展趋势与研究方向。